Teeth-cutting lathe attachment



eb 1927 s. HELFGOTT TEETH dUTTING LATHE ATTACHMENT 2 Sheets-Sheet 1 Filed March 26. l92$ avwewtoi Feb, 15, 1927.

S. HELFGOTT TEETH CUTTING LATHE ATTACHMENT Filed March 26, 1925 2 Sheets-Sheet 2 Patented Feb. 15, 1927.

UNITED STATES SOLOMON HELFGOTT,

OF NEW YORK, N. Y.

TEETH-CUTTING LATHE ATTACHMENT.

. Application filed March 2d, 1926. Serial No. 97,517.

This invention relates to lathe attachments and more particularly to a novel and improved teethcut-ting attachment for making watch wheels.

One of the objects .of my invention is to construct a lathe attachmentfor watch makers wherein the disks or blanks may be cut to provide a redetermined number of peripheral teeth with rapidity and accuracy.

Another object of my invention is to construct a lathe attachment for watch makers, designed to cutteeth in disks or blanks, being constructed and arranged so that the said disks or blanks may be moved verticallyjin the path of a cutting element during each successive tooth cutting operation.

A further object of my invention is to construct a watch makers lathe attachment for cutting gear teeth wherein the disk or blank may be intermittently advanced a predetermined distance on a vertical axis and then moved in the path of a cutting element through suitable reduction gearing.

To enable others to more fully understand and ap reciate my invention to fully comprehen the underlying features thereof that they may embody the same in the various modifications in structure and relation of parts, contemplated, drawings depicting a preferred form have been annexed as a part of this disclosure, and wherein Fig. 1 is a front view of a lathe showing the teeth cutting attachment.

Fig. 2 is a plan showing the teeth cutting attachment removed from the lathe.

Fig. 3 is' a front view of the gear housing taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a sectional view of the gear housing taken on the line 44 of Fig. 3.

Fig. 5 is a sectional View of the gear housing taken on the line 5-5 of Fig. 4.

' Fig. 6 is a partial top plan of the blank or disk supporting means.

Fig. 7 is a similar view showing the supporting means and the blank or disk in dotted lines.

Fig. 8 is a front view partly in section showing the blank or disk in position, the rear guide being shown in dottedlines.

Fig. 9 is a sectional view taken on the line 9-9 of Fig. 5. I

Fig. 10 is a sectional view showing the double gear when locked.

Fig. 11 is-a bottom plan of the upper gear.

Fig. 12 is a sectional view taken on the line 1212 of Fig. 11.

Fig. 13 is a top view of the lower gear.

Fig. 14. is a sectional view taken on the line 1 114 of Fig. 13.

Fig. is a plan of the supporting post and collar.

Fig. 16 is a sectional view taken on the line 1616 of Fig. 15.

Fig. 17 is a view partly in section showing one form of blank ordisk holder and centering means. i

Fig. 18 is a View showing a modified form of blank or disk holder.

Referring now to. the drawings wherein like reference characters designate corresponding parts throughout the several views, 5 designates thebase and 6 the horizontal guidebar of a conventional type of watch makers lathe provided withlthe usual shaft bearings and support 7 for the shaft 8 on which cone pulley 9-is mounted, said shaft being driven throughany suitable source of power such as an electric motor.

The lathe carries a block 10 mounted on a transverse dovetailed guide which may be moved and adjusted horizontally by means of the crank handle 12. A bracket 13 has a top portion 14-. overlying the block 10 which may have a threaded boss 15 and a fastening screw 16 whereby said bracket and block are securely connected for longitudinal and horizontal movement on the lathe relative to a cuttin disk 17 keyed to the shaft 8 as shown by Fig. 2. t

On the vertical portion 18 of the bracket, a wedge shaped recess or groove is provided to receive the wedge extension 19 of a gear housing 20. A vertical adjusting screw 21 having an operating handle 22 is positioned on the top of the bracket and extends within a threaded aperture 23 of the wedge extension 19 whereby the gearhousing may be raised and lowered with respect to the shaft 8 and cutting disk carried thereby.- An adjustable-stop screw 24 adjacent the adjusting screw is adapted to lock the gear housing in the required position.

The gear operating shaft 25 is provided with a worm 26. the inner end of said shaft being supported by a plate 27, fastened by screws to the rear face of the said housing. Keyed to the shaft and fastened to the plate 27 is a ratchet and pawl 28,29.

()n the shaft and outside the housing there is provided a graduated, loosely mounted ratchet wheel 30, controlled by a pivoted pawl 31 and spring 31". A lever 32 loosely mounted on the shaft 25 adjacent the ratchet wheel is adapted to engage a pin 33 on said ratchet wheel which limits the movement and operation of said lever in one direction, there being a second pin 33 on the face of the gear housing which limits the movement of the said lever in theopposite direction. Keyed to the same shaft 25 is a ratchet 34- cooperating with a spring held pawl 34 carried by the lever 32 whereby the shaft 25 may be rotated in one direction only. It will thus be seen that by setting the graduated toothed wheel or ratchet 30 to various set positions and thus limit the operation or throw of the lever, that the rotary movement of the shaft carrying the worm 26 may be regulated to operate the reduction gears now it) be described.

It is well known that there is always a certain slight movement or space between the teeth of a worm gear and a gear meshing therewith. In the cutting of gear teeth on wheels of larger diameters. this slightmovement does not materially affect the accuracy of the work. However, in cutting teeth for very small wheels suchas watch wheels and small gears, the slightest movement of which will materially affect the work. Consequently it is necessary that there be no movement or play between the worm gear and the reduction gearing. In order to produce this condition and operation and obtain absolute accuracy in cutting the teeth on watch wheel blanks, I provide a vertical post or spindle 37 having a collar 38. A top and bottom gear plate 39. 40 is mounted on the spindle and overlies the collar 38. Each gear plate is provided with peripheral teeth which mesh with the threads on the worm wheel as shown by Fig. 5 ofthe drawing. The top plate 39 is formed to provide a segmental slot 41 in which a spring 42 is positioned. A pin 43 on the bottom plate is adapted to be inserted within the segmental slot 41 so as to bear against the end of the spring 42. By reason of the spring. the bottom plate may be moved slightly, about the distance of two or three teeth, relative to the top plate since the locking screws43 connect the collar 38 to the bottom plate 40. The screws 43 are adapted to be threaded into the threaded sleeves 38 of the collar 38 but when the gears are assembled in meshing relation with the worm gear, as the screws 43 are partially unthreaded, the

r spring 42 tends to return the gear to its normal position with the result that the teeth thereof frictionally engage the teeth of the Worm gear and prevents any looseness that might tend to cause irregularity and inac-' curacies in the work. ness of the gearing teeth and the worm wheel isprevented since thereis frictional contact at all times. The said plates are further provided with aligned threaded apertures whereby they may be fastened to the collar above referred to. It will be understood that while the top and bottom plates are in a sense locked, the teeth of the plates mesh with the worm wheel so as to properly operate and rotate the spindle or post 37 on which the blanks or disks to be cut are supported and mounted in the manner now to be described.

Within the spindle orpost 37 is a key 44 internally threaded as at 45 having a beveled shoulder 47 which is seated on the top of the spindle or post 37. In the simplest form of the disk or blank locking or retaining means, a lock nut 48 is threaded on the stem 49 against the blank 50, see Fig. 18. In the modified form of the disk or blank locking means I may provide a plunger 51 having a conical shaped head 52 seated on a small tension spring 53. The conical head is adapted to pass through the hole or aperture in the blank or disk and the top member 54: of the key 44- is further provided with headed pin 55 and tension spring 56 cooperating with the point of the conical head 52 whereby the disk. or blank 50 is properly seated and ready to be moved toward'the cutting disk. "It will of course be understood that a, plurality of such disks or blanks may be cut in one operation and that it. is essential that the disks be held stationary during the teeth cutting operation.

\Vhile the disks or blanks to be cut are locked in this manner, it has been found hat the cutting disk 17 which is mounted on the horizontal shaft 8 has the tendency to press down or bend the disks or blanks. In order to revent this and to maintain all the disks 1n their horizontal position at all times during the cutting operation, I have provided a segmentaldisk supporting shoulder 56 on the top portion of a substantially semi-circular collar 57 secured to a sliding plate 58 by suitable pins 59. The sliding plate and collar 57 are movable over a slot 60 'and are in direct line with the edge of the cutting disk 17. The collar 57 and the plate arcv thus movable toward the disk or blank supporting spindle or post and the collar forms a support for the edge of the blanks or disks. In order to bring the collar in proper position and in spaced relation with the spindle or post and the edge of a disk or blank of any size or diameter, the plate 58 i.) rormed with a slotted rearward extenzion 61. The

In this manner loose- Hill slot 62 of the extension is adapted to receive the screw 63 fixed in the bed of the housing and thus guides the extension in its rearward or forward movement. A second slotted plate (54: is provided with a curved arm having a vertical portion 66 which bears against the edges of the disks or blanks directly opposite to the' cutting disk. The

inner edges of the slotted plates 58 and (34' 'normally tending to move said plate inwardly toward the disks orblanks. ()n the other hand the plate.61 and the collar carried thereby is properly'spaced by reason of the engagement of the vertical portion (36 of the. curved arm which bears against the periph cry of the disks or blanks. Consequently, the collar which forms a seat for the edges of the disks or blanks maintains them in perfect horizontal alignment while being cutby the cutting disk.

A segmental top housing 73 is fastenedto the housing 20, said housing being provided with a boss-74 and a screw 75. which is threaded to engage the-tip of the post or stem 4(nas shown by Fig; 5 of the drawing.

In theatual use and operation of the at- "tachment tl e operator adjusts the position of the bloc 10 on the lathe so as to bring the attachment toward the cutting disk 17 on the shaft 8. The housing for the reduction gearing is then raised or lowered by the screw 21 and the operating handle 22. The disks to be cut are first positioned on the spindle or post 46 and are locked to rotate therewith. After the first tooth is cut, the operator then swings the lever 32 according to the position of the graduated toothed Wheel 33, which operationadvances or rotates the spindle46 through the reduction gearing the required distance. mien so advanced, the operator may then rotate the screw 91 by the handle whereby tl10 diSkS or blanks are brought into engagement with the cutting disk to out] the next'tooth. It will-of course be tm(lerstood that the. thro-w'o'f the lever beingregulated or limited, the spacing of the teethis accordingly obtained as in some instances it will be required that a disk or blank shall contain varying number of teeth. In this operation and practice, there are but two movements or operations necessary-and yet the, cutting disk and the blanks or disks to be cut-remain fixed. The vertical movement of the entiregearinghousing and the fixed blanks or disks in the path of the rotary cutter ettects the same 'cut at each 'the operation. Thespacing of thefixed blanks or disks through the reduction gearing insures that the proper number of teeth may be cut. In this manner, a high degree of extreme accuracy is obtained such as is required in precision work in producing watth wheels of very small diameter.

Having shown and described my invention what I now claim as new and desire to se: cure by Letters Patent of the U. S. is:

1. In a wheel cutting fixture for lathes, the combination of an attachment comprising a gear housing and sectional and yielding reduction gears therein, means to adjusting said housing'relative to a cuttingelement ot said lathe, disk or blank supporting means rotatable by the reduction:

gears, a bearing shoulder for said disk or blank whereby it is maintained in horizontal alignment to the action of the cutting element, means for engaging the rear edge of said blank or disk on the supporting means and means for intermittently advancing a disk or bla-nkon said supporting means by the gearing.

2'. In a wheel cutting fixture for lathes, the combination of an attachment: comprising a gear housing and sectional and yielding reduction gears therein, means for adjusting said housing relative to a cutting element of said lathe, disk or blank supporting means rotatable by the reduction gears, a freely movable bearing shoulder for said disk or blank whereby it is maintained in horizontal alignment to the action of the cutting element. means for engaging the periphery of said blank or disk at a point opposite to the bearing shoulder and means for intermittently advancing a disk or blank on said supporting means by the gearing.

3. In a wheel cutting fixture for lathes,

ing a gear housing and sectional and yielding reduction gearstherein', means for adjusting said housing relative to a cutting element of said. lathe, disk or blank supporting means rotatable with the reduction gears, a freely movable bearing shoulder constituting a rest on ;which the blank or disk is positioned to the action of the cutting element and means cooperating with the bearing shoulder for engaging the periphery of said blank or disk at a point opposite to the said shoulder and cutting element of the lathe.

4. In a wheel cutting fixture for lathes, the combination of an attachment comprising a gear housing and reduction gears therein, means for adjusting said housing relative to a cutting element of said lathe,

disk or blank supporting means rotatable.

with the reduction gears,a sliding plate having a bearing shoulder on which said disk or blank may be locked, a second sliding plate cooperating with the first mencombination of an attachment compris- 3 the tioned plate and having an arm for engaging the disk or blank at apoint opposite said bearing shoulder and lever operated means for rotating the gearing to advance and rotate the said disk or blank.

5'. In a. wheel cutting fixture for lathes,

combinationot' an attachment comprising a gear housing and sectional and yielding reduction gears therein, means for adjusting said housing relative to a cutting element on the lathe, disk or blank supporting means rotatable by the reduction gears,- a movable bearing shoulder for the edge of a disk or blank, means for locking the said disk or blank and lever operating means for actuating said gearing whereby the said disk or blank may be intermittently advanced a predetermined distance.

6. In a wheel cuttingfixture for lathcs, the combination of an attachment comprising a gear housing and sectional and yielding reduction gears therein, means for adjusting said housing relative to a cutting element on the lathe, disk or blank support ing means rotatable by the reduction gears, a lever for actuating said gears in one direction only, and stop limiting means for said lever whereby the said disk or blank may he intermittently advanced a predetermined distance. v

7. In a wheel cutting fixture for lathes, the combination of an attachment comprising a gear housing and sectional and yielding reduction gears therein, an operating shaft for said gearing, a disk or blank supporting means operable by the reduction gears, a ratchet wheel keyed on the operating shaft, a lever freely movable on the shaft, a pawl carried by said lever and cooperating with the ratchet wheel and means for limiting the movement of the said lever mg reduction gears therein, a bracket havmg means tor connection to a movable part on the lathe, said bracket being formed with a groove and adapted to slidably receive one end of the gear housing, an ad justing screw for raising and lowering the gear housing relatively to a shaft and rotary cutter thereon, a disk or blank supporting means operable with the reduction gearing and lever operated means for actuating said gearing whereby the disk or'blank may be intermittently advanced a predetermined distance.

-9. In a wheel cutting fixture for lathes, the combination of an attachment comprising a gear housing and means for raising and lowering said housing relative to a shaft and a rotary cutter thereon, an operating shaft and worm gear in said housing, a sectional gear plate having teeth meshing with the worm wheel, resilient means for maintaining the teeth of said Worm gear and sectional gear plate in constant mesh and engagement, a blank or disk supporting post operable with the gearing, means for locking a blank or disk on the post, an operating shaft for said gearing, ratchet and pawl mechanism for actuating the shaft in one direction including a loosely mounted lever on the shaft and stop limiting means whereby said disk or blank may be advanced intermittently and througha predetermined distance.

In testimony whereof I affix my signature.

SOLOMON HELFGOTT. 

